Cleanup references when turning BT off.

Bug: 5572649
Change-Id: I62f9e0620832b69995d5c6e1c24634c9a3895a4b
diff --git a/core/java/android/bluetooth/BluetoothInputDevice.java b/core/java/android/bluetooth/BluetoothInputDevice.java
index 282b70a..1a9e011 100644
--- a/core/java/android/bluetooth/BluetoothInputDevice.java
+++ b/core/java/android/bluetooth/BluetoothInputDevice.java
@@ -118,6 +118,10 @@
         }
     }
 
+    /*package*/ void close() {
+        mServiceListener = null;
+    }
+
     /**
      * Initiate connection to a profile of the remote bluetooth device.
      *